The Search > Lookup References command can be used to quickly find all references to the word in the current selection. For example, to find all calls to TextOut, put the insertion point inside of the TextOut identifier and run the Lookup References command. A Search Results window will be built which will list all references found. See: Lookup References.
The Relation Window can also be used to show references automatically to the word in the current selection. See: Relation Window.
The Project Search Bar and the Search > Search Project command can be used to search across your whole project, using a powerful keyword and name fragment based search. This is like an Internet search across your project.